Major Depressive Disorder (MDD) is a highly prevalent mental disorder that interferes with individuals' daily functioning. MDD has been shown to be readily treatable as findings suggest that most patients achieve some level of remission. Conversely, the likelihood of relapse is also a significant complication. While the clinical lore suggests that early intervention for MDD benefits treatment outcome, the empirical validation of this assumption remains inconclusive. Recently, Quiring, Monroe, Simons, and Thase (2000, submitted for publication) showed that delayed intervention was actually predictive of better long-term course. Indeed, there needs to be an extensive investigation concerning the utility of early intervention. The current project will utilize the NIMH Treatment of Depression Collaborative Research Program (TDCRP) dataset now available publicly. The primary objective is to evaluate the benefits of early intervention for MDD. The secondary objectives include the following: 1) to assess treatment modality issues (i.e., antidepressant pharmacology versus psychotherapy) as they pertain to early intervention, 2) to assess treatment modality issues as they pertain to indices of both short-term as well as long-term outcome, and 3) to make treatment specific recommendations as they pertain to early intervention and course.